An ink jet type image forming apparatus having an ejection head for ejecting ink to form an image is known in the art.
According to one kind of the ink jet type image forming apparatus, an ink cartridge system is provided such that a cartridge can be replaced by a new cartridge to replenish ink to a main body of the apparatus. According to another kind of the ink jet type image forming apparatus as described in Japanese Patent Application Publication No. 2012-71585, a liquid supply system is provided in which a user replenishes ink to an ink tank provided at an outside of the image forming apparatus, and the ink replenished in the ink tank is sucked at negative pressure and is supplied to the main body of the image forming apparatus.